javascript - Can I use jQuery to check whether at least one checkbox is checked?

Question

I have the following HTML form which can have many checkboxes. When the submit button is clicked, I want the user to get a javascript alert to check at least one checkbox if none are checked. Is there an easy way to do this using jQuery?

<form name = "frmTest" id="frmTest">
  <input type="checkbox" value="true" checked="true" name="chk[120]">
  <input type="checkbox" value="true" checked="true" name="chk[128]">
  <input type="checkbox" name="chk[130]">
  <input type="checkbox" name="chk[143]">
  <input type="submit" name="btnsubmit" value="Submit">
</form>

Answer 1

if(jQuery('#frmTest input[type=checkbox]:checked').length) { … }